A method of and apparatus for filling a volatile liquid into at least one tank (10) of a multi-tank installation having a vent-pipe (11A, 11B . . . 11F) associated with each tank, all of the vent-pipes being connected to a common vent manifold (13) through respective over-pressure valves (12A, 12B . . . 12F). A vapor extraction manifold (16) is also connected to each over-pressure valve (12A, 12B . . . 12F) and during a tank filling operation is coupled to a vapor extraction mechanism. Both the vent manifold (13) and the extraction manifold (16) are provided with pressure sensitive valves (15, 19) respectively to allow air to enter the manifolds from the ambient when the pressure within the respective manifold falls below atmospheric. On filling any one of the tanks (10), the gas displaced from that tank is distributed amongst all of the tanks until the pressure within all of the tanks reaches some pre-determined value, whereafter the valve (12) associated with the tank (10) being filled operates to connect that tank's vent-pipe (11) to the extraction manifold (16).